Gaseous detectors based on large-size GEM-foils are planned to be used for a variety of upgrades and new experiments using high-rate and high-intensity particle beams. An excellent quality control of ...GEM-foils is a mandatory prerequisite to select the best foils for the assembly of a GEM detector. The high voltage stability of the foils is here of uppermost importance. In particular discharges that occur at the same position need to be detected. A spark detection system has been developed to automatically detect and record the time and position of sparks. The system is based on a commercial web camera installed in a housing for the tests and a custom-made, LabVIEW-based software for control and operation. An automatic Spark-Detection System for GEM foils was designed, built and characterized. It is able to detect and record discharges in large-size GEM foils during the quality control procedure. The spark detection e ciency was estimated to be higher than 97 %, the position resolution was determined to be approximately 0.5 mm. With this system, the characterization of GEM foils can be standardized to a much greater degree than before.
With the planned upgrade of the ALICE Time Projection Chamber (TPC) the current readout technology will be replaced by a Gas Electron Multiplier (GEM)-based readout technology in order to allow for a ...continuous operation at high interaction rates up to 50 kHz. A stack of four GEM stages with non-standard field configuration was chosen to achieve a suppression of the ion backflow below 1%, while maintaining a good energy resolution below sigma / E= \unit12% for super(55) Fe. A discharge probability of 10 super(-10) for alpha-particles was confirmed for this low ion backflow field configuration. This is comparable to standard triple GEM detectors in low discharge settings. To upgrade all the Inner and Outer Readout Chambers of ALICE, 576 GEM foils will be needed. Only GEM foils that fullfill the highest quality criteria can be used. Therefore a quality assurance scheme has been developed that includes a large set of quality assurance measurements.
Abstract
The target asymmetry
T
, recoil asymmetry
P
, and beam-target double polarization observable
H
were determined in exclusive
$$\pi ^0$$
π
0
and
$$\eta $$
η
photoproduction off quasi-free ...protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the
$$\gamma p \rightarrow \pi ^0 p$$
γ
p
→
π
0
p
and
$$\gamma p \rightarrow \eta p$$
γ
p
→
η
p
reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the
$$\eta n$$
η
n
system at
$$W = 1.68\ \textrm{GeV}$$
W
=
1.68
GeV
. A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the
$$S_{11}(1535)$$
S
11
(
1535
)
and
$$S_{11}(1650)$$
S
11
(
1650
)
resonances within the
$$S_{11}$$
S
11
-partial wave.
The target asymmetry
T
, recoil asymmetry
P
, and beam-target double polarization observable
H
were determined in exclusive
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\usepackage{amsmath}
\usepackage{wasysym}
...\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\pi ^0$$\end{document}
π
0
and
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\eta $$\end{document}
η
photoproduction off quasi-free protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\gamma p \rightarrow \pi ^0 p$$\end{document}
γ
p
→
π
0
p
and
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\gamma p \rightarrow \eta p$$\end{document}
γ
p
→
η
p
reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\eta n$$\end{document}
η
n
system at
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$W = 1.68\ \textrm{GeV}$$\end{document}
W
=
1.68
GeV
. A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$S_{11}(1535)$$\end{document}
S
11
(
1535
)
and
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$S_{11}(1650)$$\end{document}
S
11
(
1650
)
resonances within the
\documentclass12pt{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$S_{11}$$\end{document}
S
11
-partial wave.
The goal of the project SFB588 supported by the Deutsche Forschungs-gemeinschaft (DFG) is to generate concepts, methods and a concrete prototype of a humanoid robot. The intended application area is, ...for instance, a generic kitchen, where the robot is planed to perform actions autonomously at the user's request. In this paper, a model of stable analysis of a humanoid robot is given, in which the different environments are considered. By introducing a concept of fictitious zero-moment (FZMP), a method to maintain the whole body stability of robot under disturbance is presented. The support polygon and the rotation edge in the case of losing balance are determined by means of simulation. In order to maintain stability in different environments a new control strategy is presented including the adjustment of the support polygon, the push or pull support of hand with environment, the movement of upper robot body. The relative position between FZMP and support polygon is specially emphasized. The feasibility of the proposed method is demonstrated through the simulation.
The development of a humanoid robot platform within the scope of the collaborative research centre 588 has the objective of creating a machine that closely cooperates with humans. This development ...area presents a new challenge to designers. In contrast to industrial robots - for which mechanical rigidity, precision and high velocities are primary requirements - the key aspects here are prevention of hazards to users, a motion space that corresponds to that of human beings and a lightweight design. In order to meet these requirements, the robot must have humanlike appearance, motion space and dexterity. Additionally, its kinematics should be familiar to the user, its motions predictable, so as to encourage inexperienced persons to interact with the machine. This article gives insight into the design of the mechatronic components of the upper body of the humanoid robot ARMAR III. Due to the special boundary conditions for the design of such a humanoid robot and complex interaction between system elements, the design process is very challenging. The robot has a modular structure. The modules for neck, torso and arms were designed and built at the Institute of Product Development (IPEK) at the University of Karlsruhe (TH). The design of these modules of the upper body and the problems solved by these designs are presented in this article
With the development of humanoid robots, lightweight construction and energy efficiency play an important role. In state-of-the-art processes and methods concerning structural optimization it is ...assumed that there exists a set of external loads or load functions acting on the part. But humanoid robots are very complex mechatronic systems. The fact that the system's dynamic properties and its overall behavior may change due to geometric modifications of a part caused by an optimization process is typically neglected. In order to take into account the interaction between the part, dynamic system, control system and the changing mechanical behavior with all its consequences for the optimization process, a simulation of the complete mechatronic system is integrated into the optimization process within the research work presented in this paper. A hybrid multibody system (MBS) simulation, that is, a MBS containing flexible bodies, in conjunction with a co-simulation of the control system represented by tools of the Computer Aided Control Engineering (CACE) is integrated into the optimization process. By an inner optimization loop the controller parameter are adopted new in each iteration of the topology optimization in order to provide realistic load cases. The research work presented in this paper is a contribution towards the integration of existing CAE methods into a continuous process for structural optimization. The benefits will be illustrated by an optimization of parts of the humanoid robot ARMAR of the collaborative research centre for ¿Humanoid Robots¿. The new process allows an efficient optimization of structures ¿within¿ their surrounding mechatronic system.
With the development of humanoid robots, lightweight construction and energy efficiency play an important role as these mobile, dynamic systems have to work self-sufficiently. In state-of-the-art ...processes and methods concerning structural optimization it is assumed that there exists a set of external loads or load functions acting on the part. But humanoid robots are very complex mechatronic systems. The fact that the systempsilas dynamic properties and its overall behavior may change due to geometric modifications of a part caused by an optimization process is typically neglected. In order to take into account the interaction between the part, dynamic system, control system and the changing mechanical behavior with all its consequences for the optimization process, a simulation of the complete mechatronic system is integrated into the optimization process within the research work presented in this paper. A hybrid multibody system (MBS) simulation, that is, a MBS containing flexible bodies, in conjunction with a co-simulation of the control system represented by tools of the computer aided control engineering (CACE) is integrated into the optimization process. The benefits will be illustrated by an optimization of parts of the humanoid robot ARMAR of the collaborative research centre for ldquoHumanoid Robotsrdquo. Especially the optimization of two parts at a time within one optimization loop allows an efficient optimization of structures ldquowithinrdquo their surrounding mechatronic system.
With the development of humanoid robots, lightweight construction and energy efficiency play an important role as these mobile, dynamic systems have to work self-sufficiently. The application of ...computer-aided (CAE) methods in the development process is one possibility to achieve the required weight reduction. On the basis of a classical topology optimization carried out on the robot ARMAR III, an extended system-based method for dynamic, mechatronic systems is presented. Different analysis domains, namely hybrid multibody system dynamics (MBS), finite element analysis (FEA), control system simulation and topology optimization are integrated into a straightforward, automatic way. For the use of fiber reinforced composite materials in such parts, a FE-based method for the determination of ply orientations and thickness relations is presented.
The development of a humanoid robot within the scope of the collaborative research centre 588 has the objective of creating a machine that can closely cooperate with humans. This development area ...presents new challenges for designers. In contrast to industrial robots - for which mechanical rigidity, precision and high velocities are primary requirements - the key aspects here are prevention of hazards to users, a motion space that corresponds to that of human beings, and a lightweight design. In order to meet these requirements, the robot must have humanlike appearance, motion space, and dexterity. Additionally, its kinematics should be familiar to the user, and its motions predictable, so as to encourage inexperienced persons to interact with the machine. This article gives insight into the design of a new wrist for the next generation of the humanoid robot ARMAR. The goals of the development project are both to improve the motion space and to achieve a humanlike appearance. The new mechanical design is described in detail completed by a study of a first prototype.
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